A device for screwing on caps generally comprises a stationary structure, a platform mounted to pivot on the stationary structure, and rotary spindles mounted on the platform. Each rotary spindle has a first end provided with a head for gripping caps, and a second end connected via a torque limiter to a drive shaft having a gearwheel meshing with a toothed wheel secured to the stationary structure. There exist magnetic torque limiters comprising a magnetic bell constrained to rotate with the drive shaft and a magnetized magnetic core constrained to rotate with the spindle and slidably received in the bell so that the bell and the core are coupled together magnetically. The depth to which the core is engaged in the bell determines the maximum torque that can be transmitted from the bell to the core, and thus the tightening torque. At the end of screw tightening, the gripping head is opened to release the closed receptacle. When the clamp opens, it starts turning again. Opening the clamp while torque is being exerted thereon thus runs the risks of scratching the cap and of wearing the clamp prematurely. In order to remedy that drawback, it is necessary also to provide a clutch to enable the spindle to be decoupled from the drive shaft.